1. Field of the Invention
This invention relates to a fabric useful in a system for monitoring motion, such as the motion generated by a geometric change in a body in response to physiological activity.
2. Description of the Prior Art
Heart rate monitors are known for measuring and reporting the heart beat of humans and animals. Such monitors receive signals from the pulsating flow of blood synchronized with the periodic pumping activity of the heart. Typically, the known monitors detect the pulsating flow of blood through a sensor in a chest belt or through a sensor clipped mechanically to an ear or finger. U.S. Pat. No. 5,820,567 (Mackie) describes a representative arrangement of a chest belt or an ear clip for a heart rate sensing apparatus.
A chest belt is difficult to fit and often requires gel to wet the sensor electrodes prior to use. Tight chest belts for heart monitoring can be uncomfortable if worn for a prolonged period. Mechanical sensors that clip to a finger or an ear can also be uncomfortable.
The QuickTouch™ heart monitor sold by Salutron Inc. (Fremont, Calif. 94538, USA) eliminates the chest strap, finger or ear clip to measure heart rate in all phases of exercise. However, while eliminating cumbersome wires and straps, two points of body contact are required in operation. This device thus requires application of two fingers on a watch band, two hands on a treadmill, or two hands on a bicycle handle bar to give heart rate readings. As a result, this device does not totally free the subject from the monitoring process.
Systems that relieve the monitored subject from the discomfort of chest belts or clip devices to the finger or ear, and from the inconvenience of being restricted to the monitoring apparatus, have been disclosed.
U.S. Pat. No. 6,360,615 (Smela) discloses a monitoring system using a garment that detects motion in the body of the wearer through a strain gauge implemented using a polypyrrole-treated fabric.
U.S. Pat. No. 6,341,504 (Istook) discloses a garment for physiological monitoring comprising one or more elongated bands of elastic material with conductive wire formed in a curved pattern. When the garment is worn by a human, the elongation and relaxation of the fabric caused by geometrical changes of the human frame induce electrical property changes in the conductive wire(s) of the garment. Such a system adds an additional component of complexity to the fabric structure, which is not well-suited to traditional garment design and construction.
U.S. Pat. No. 4,909,260 (Salem) describes a bulky waist belt system for physiological monitoring.
U.S. Pat. No. 5,577,510 (Chittum) describes bulky chest and waist belts for physiological monitoring.
Patent Publication WO 9714357, Healthcare Technology Limited, Great Britain, discloses a monitor capable of generating an audio heartbeat message.